Abstract
Purpose :
The purpose of this study is to develop mathematical models to simulate the tear film dynamics on an eye-shaped domain during a realistic blink cycle. In the model we examine the influence of the blink on tear film formation. To our knowledge, this is the first mathematical model of tear film dynamics during blinking over the whole exposed ocular surface, and experimental methods do not yet have the capability to estimate the tear film thickness in the same detail. Therefore, the model is expected to improve understanding of tear film formation and to make predictions that may be experimentally tested in the future.
Methods :
We formulate a mathematical model for the moving eye-shaped domain via a computational least-squares fit to the lid margins from a video recording of a blink. The result becomes the moving boundary for the simulation of tear film dynamics derived using a thin film approximation to the fluid flow inside that moving domain. The model includes surface tension, viscosity, evaporation and wetting of the ocular surface. We then implemented a moving overset grid method to numerically approximate the thin film equations for the tear film dynamics. The numerical approach is implemented in the Overture framework.
Results :
The formation of the tear film over the eye during the upstroke is sensitive to the speed of lid motion, as well as to boundary fluxes from lacrimal supply and punctal drainage. A sufficiently large supply of aqueous of tear fluid under the moving lids is required for adequately coating the ocular surface. Our results will be closely compared with prior modeling results as well as available experimental results.
Conclusions :
A simulation of the tear film dynamics on a blinking eye-shaped domain was created and its influence on the tear film formation during the upstroke was studied. We proposed quantities that are candidates for experimental verification.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.